Means for cooling piercing points of tube rolling mills



March w, W41. .,J. W. WELS@ 23345971 MEANS FOR COOLING PIERCING POINTS OF TUBE ROLLING MILLS Filed July 22, 1939 1 A Ly lll/)2i /6 mei/56'07". l5 I4 JOHN /4/ KELSO,

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.lohn W. llilelso, hast ltllcllieesport, limon, aiesignor to `hlainlonall rlluhe ilornpany, a corporation of liiew llersey iippllication .liully ZZ, lilith, Serial No. Zfidill il filatura'.

This invention relates to tube or pipe rolling mills and, particularly, to an improved means for cooling the piercing points thereof.

ln, one method of manufacturing pipes or tubes, as is well known to those skilled in the art, it is the practice to provide a mandrel har having a piercing point on the end thereof and to initially forni the tube or -pipe by forcing a solid hot billet over the piercing point and man drel har, thereby piercing the same which, of course, results in the shell surrounding and enclosing therein both the mandrel bar and the piercing point during the piercing operation. Consequently, the mandrel har and piercing point become extremely hot and overheated after a short period of use and become distorted, thereby rendering them unfit for further use. -lit is now the general practice to cool the mandrel hars by' making them hollow and supplying a cooling fluid thereto to cool the same, thereloy the heat absorbed thereby from the hot steel billets. lt will he seen that if these piercing points are permitted tohecorne overheatedfwhich easily happens in the case of a relatively long shell especially of a small diameter, they will reach such a heat that the points thereof become hlunt and distorted which renders themuniit for further service and necessitates a replacementv thereof.

accordingly, it is one of the objects of the present invention to provide an improved means for cooling piercing points of tube or pipe rolling mills 'which is very effective in its operation and use, thereby completely dissipating the heat therefrom.

ft is another object of the present invention toA provide an improved means for cooling piercing points ofqtube or pipe rolling mills which is simple and inexpensive in its construction, and, at the same time,` one that is rugged and easily maintained.

liarious other objects and advantages of this invention will hecome more apparent in the course of the following specification, and will particularly pointed out in the appended claims.

fn the accompanying drawing there is shown, for the purpose of illustration and description, one embodiment which my invention may assume in practice.

ln the drawing:

Figure l is a plan partly inA section of the im- (lUi, dim-lli) proved means for cooling` piercing points of my invention;

Figure 2 is an elevation partly in section thereof;

Figure 3 is an enlarged plan partlyin section of the mandrel cap; and Figure l is a sectional View talren on lines IV-TV of ligure 3.,

Referring more particularly to the drawing, there is shown a pair of driven metal-working rolls i and guides fr of the conventional type for drawing a hot steel billet over a piercing vpoint t and hollow mandrel har t to pierce and elongate the same, a practice which is well known to those slrilled in the art.

According to the present invention, there is disposed on the outer end of the mandrel bar lli, between the end thereof and the piercing point ii, a bar cap member l having a reduced inner threaded end portion il which is screwed into the outer end of the mandrel bar. On the inner end of the bar cap l, there is arranged an outwardly tapered or tang portion t of a relatively small diameter on which the piercing point t is loosely disposed.

The inner portion ill of the intermediate part of the har cap- 'l has an outer diameter substantially equal to the outer diameter of the mandrel har t and the outer portion if of the intermediate part of the bar cap has an outer diameter slightly smaller than the outer diameter of both the mandrel har and piercing point so as to provide an angular shoulder portion if around the outer edge of the inner portion it.

There is arranged axially of the har cap 'l and extending from the inner end thereof through the reduced portion t to a point intermediate the bar cap, a cooling iiuid passageway ifi which has preferably a threaded portion ita on the outer end thereof by which the har cap is connected to a cooling fluid supply line within the mandrel bar t.

'llhere is disposed within the inner portion lll of the intermediate part of the har cap l around the passageway it, a plurality of radially extending fluid passageways it communicating therewith and there is angularly arranged in and around the angular shoulder portion it thereof an equal numher of orinces or jets it which communicate with the passageways iii. The part of the reduced outer portion if of the bar cap next to the angular flange portion it is preferably tapered or angularly arranged and the orifices or ,iets it are preferably arranged tangential or parallel thereto .so that a circular spray lll ddr

is formed as the cooling fluid issues from the jets thereagainst and is directed outwardly thereby against the inner walls of the shell Il being formed from the billet at substantially the point of the contact of the same with the largest diameter of the piercing point, as is shown in Figure 1. It will be understood that the cooling uid, preferably water, is introduced under pressure from a source of supply into and through the hollow mandrel bar 6 into the passageway Il in the bar cap 1, into and through the radially extending passageways l-5 and out through the angularly arranged jets or orifices I6 in the angular shoulder portion I3 against the angular surface of the portion l2, thereby forming a circular spray which is delivered against the inner walls of the shell I1 at the piercing point as the shell is being formed, thereby cooling the piercing point as well as the walls of the shell. It will be noted that, due to the shell assuming an oval sectional conformation in the working zone, as lshown in Figure 2 of the drawing, two cavities are formed, one at each side of the shell between the inner surface thereof and the piercing point, that is, there is always a clearance therebetween at the sides of the piercing point on which the guides 3 are disposed during the drawing operation, thereby permitting the cool- Iing fluid to pass along the exterior surface of the piercing point at these points so as to reach practically the entire exterior surface of the same.

lAs a result oi my invention, it will be seen that there is provided a cooling means 'which quickly and eiectively dissipates the heat absorbed by the piercing point from the hot steel billet, thereby eliminating the danger of the piercing point from becoming overheated and distorted.

While I have shown and described an embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description, and that various other forms may be devised Within the scope of the invention, as defined in the appended claims.

I claim: l. In a tube rolling mill, a mandrel bar, a piercing point disposed on .the outer end of said mandrel bar, said mandrel bar being constructed and arranged so that a cooling uid can be conveyed therethrough. and means arranged on the end of said mandrel bar for delivering the cooling fiuid outwardly from the end thereof toward said piercing point whereby the .cooling iiuid is directed over and around the exterior surface of the piercing rpoint so as to cool the same.

2. In a tube rolling mill, a. mandrel bar, a piercing point 'disposed on the end of said mandrel bar, said mandrel bar being constructed and arranged so that a cooling uid can be conveyed therethrough, and means interposed between the end of said mandrel bar and said piercing point for delivering a circular spray of cooling uld from the interior of said mandrel bar Ito the exterior surface of the piercing point to cool the same. 4

3.111 a tube rolling mill, a mandrel bar, a piercing point disposed on the end of said mandrel bar, said mandrel bar being constructed and arranged so that a cooling fluid can be conveyed therethrough, means interposed between the end of said mandrel bar and said piercing rpoint for closing the end of said bar, and a plurality of jets concentrically arranged around said means communicating with the interior of said mandrel bar, said jets being arranged so as to deliver a circular spray of cooling uid from the interior of said mandrel bar .to the exterior surface of said piercing point to cool the same.

4. In a tube rolling mill, a mandrel bar, a bar cap arranged on .the outer end of said mandrel bar, a, piercing point disposed on :the outer end of said ibar cap, said mandrel bar being constructed Iand arranged so that a cooling fluid can be conveyed therethrough, a plurality of jets concentrically positioned around said bar cap communicating with fthe interior of said mandrel bar, said jets being arranged so as to deliver a circular spray of cooling fluid from .the interior of said mandrel bar to .the exterior surface of said piercing point to cool the same.

JOHN W. KELSO. 

